REFLEX EPILEPSIES

OVERVIEW

Reflex epilepsies are characterized by the presence of reflex
seizures and the absence of spontaneous seizures. Reflex seizures may
occur in epilepsies of varied etiologies (e.g. in structural brain
abnormality and in genetic/idiopathic generalized epilepsies), however these are
not categorized as reflex epilepsies as spontaneous seizures occur in
addition to reflex seizures. There are a number of recognized reflex
epilepsies; two examples are described in this section of
EpilepsyDiagnosis.org.

NOTE a reflex (also known as
stimulus-sensitive or sensory-evoked) seizure is a seizure that is
constantly elicited by a specific stimulus, which may be an afferent
sensory stimulus or an activity undertaken by the patient. Sensory
stimuli may be elementary (e.g. light flashes, patterns, elimination
of visual fixation, elimination of light, tactile, hot water, startle
or a monotone) or more complex (e.g. eating, tooth-brushing, music or
singing). A stimulus activity may be elementary (e.g. a movement) or
more complex (e.g. reading, playing chess, calculating, thinking).
Such stimuli will constantly elicit a reflex seizure in a patient with
reflex epilepsy, in contrast to facilitating stimuli that may facilitate EEG discharges
or evoke a seizure (but not constantly) in other epilepsy syndromes.

Reading epilepsy

Reading epilepsy is characterized by seizures that start between
12 and 19 years of age. There is a male predominance (1.8M:F).
Seizures are elicited by reading (aloud or silently). Prognosis is
good as seizures are usually minor and can be avoided through reducing
exposure to the stimulus.

Startle epilepsy

Startle epilepsy is characterized by seizures that may start in
childhood or early adolescence (1-16 years). Both sexes are affected.
Most patients have underlying structural brain abnormality with
neurological (e.g. hemiplegia) and intellectual disability. Seizures
are often difficult to control.